Stock Oil Pump Spring

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Aug 8, 2025 | 08:36 PM

Chris in Idaho

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Staging Lane

Joined: Feb 2023

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Stock Oil Pump Spring

I see the aftermarket pink 70lb springs but can't find any info on what psi the stock LT1 oil pump spring bypasses at. Anyone know?

Aug 9, 2025 | 05:49 PM

dixiebandit69

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From: Texas

It's 55-60 psi. You can shim a factory spring for more pressure.

Aug 10, 2025 | 09:35 PM

Fast355

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From: Euless, TX

Quote:

Originally Posted by Chris in Idaho

I see the aftermarket pink 70lb springs but can't find any info on what psi the stock LT1 oil pump spring bypasses at. Anyone know?

M155 is the stock pump. Just had one apart not long ago. Had a ~62 psi spring installed per the Melling color code.

Keep in mind the bypass spring pressure merely tells you where the bypass valve starts to open, it does not control minimum or maximum oil pressure. With the bypass fully open cold you could see 70-80+ psi and with it fully closed only 40-50 hot and less at idle. Clearences and viscosity as well as pump volume/rpm play a larger part in dictating pressure than the bypass spring.

Last edited by Fast355; Aug 11, 2025 at 04:02 AM.

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